Multicolor cinematograph and other film



May 13, 1930. J. E. THORNTON 1,758,769

MULTICOLOR CINEMATOGRAPH AND OTHER FILM Original Filed May 5, 1924 2Sheets-Sheet l Immmzf@ M2111 ey.,

May 13, 1930. .,J. E. THORNTON 1,758,769

MULT-ICoLoR CINEMATOGRAPH AND OTHER FILM Original Filed May 5, 1924Sheets-Sheet 2 Mayes Ffm/w Affe/1mm". l

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/fzzayes Par/sof/maje Fatented May 13, 1930 narran srarrfas 'igssase@PRICE MULTICOLOR CINEMATOGRAPH AND OTHER lim @riginal applicationApplications for this invention were tiled in Great Britain May 18,1923, and Feb. 15, 1924.

rlhis case is a division of Serial No. 711,254

tiled May 5, 1924.

This invention provides a new system, method vor process for theAproduction of multi-color pictures comprising either four or threecolors, in the form of continuous ciiieinatograph iilms, or any otherforms of transparencies, such as lantern-slides, window transparencies,advertisements, thin transfer tissues and the like, by entirelyphotographic methods.

The invention is designed to enable the completed pictures to beproduced as double width transparencies comprising two halfpictures eachof which contains only two colors, formed upon two lms or plates, of

so, the multi-color screen type, these two-halfpictures being producedby means of two original negatives also in the form of two half-picturesof screen-type and two intermediate printing-clichs also consisting oftwo half-pictures of screen-type.

This result is attained by the use in coinbination of several factors,including 2-the special method of producing the negatives, whichconsists in the use in combination of 3o the following elements (l)acamera, one lens, and a light-spliting device which lwill divide theimage formed by the lens into two images oi identical size; 2) a specialform of sensitive material of double-picture-area to receive these twoimages, the sensitized material having a pair of adjacent colorscreensor filters (each comprising two colors,

the colors of one screen being diii'erent fromA the colors of the otherscreen), the lens and 4o light-splitting device dividing the original.

' image into two and the color-screens of the sensitized material makinga further division by which the analysis o four or three colors arerecorded upon the one sensitive material of double-picturey-area; and(3) by producing a further record or printing clich,'in which theprimary images of the original negatives are converted int-o positiveimages ofthe printing-clich either by chemical reversal or by copying.

led May 5, 1924, Serial No. 711,254, and in Great Britain EIay 18, 1923.Divided. and this application led November 3,. 1925.

Serial No. 66,802.

Reconstruction of the split image and its colors is effected by adouble-area positive print, made from the double-area printingclich upona sensitized material of similar type and also double-area whereon twoadjacent positives or half-pictures'are formed,

each comprising two colors, and each with a diiierent pair of colorsfrom the other.

Uompmz'son with previous color systems transfer tissues, and continuouscinemato-A graph films. U

"l`he basis ,of the invention consists in dividing thepictureduring theprocess of its production into two component parts each part having adierent color-screen or filter, by doubling the area of the sensitivematerial, both for the negatives and positives, s o that the two screensare formed in two pictureareas and thus four colors are filtered.

Therefore the improved results attained by thisinvention areaccomplished :-(1) partly lby use of the doubleareak sensitive materialcomprising two screens of two colors and (2) partly by use of theoptical system which enables two images of identical size and stand-.point to be formed upon the double-area sensitive-material; and bythese joint means to secure four color analysis within the space of twopicture areas.

Incidentally the same methods are used to produce three-color picturesif they .are de' sired, by using film-material with its two screensmodified in their colorings as hereinafter described.

To the photographer, this invention presents no new points to beovercome, and only requires the substitution of a double-area camera totake the double-area screen film material of the special constructionhereinbut double-area sensitive material of the special constructionhereinafter described is used instead of ordinary sensitive material.'

In the drawings Fig. 1 is a plan view of a portion of a double widthstrip of transparent support upon which are formed two screen filters,each of Such filters comprising two colors formed of interspersed finelines of different colors'.

Fig. 2 isa view similar to Fig. 1 but with screens which will analyzeonly three colors.

Fig. 3 is a view similar to Iig. 1 wherein the screens are shown asformed of grains.

Fig. 4 is a view similar to F ig. 2 wherein the screens are shown asformed of grains.

Fig. 5 is a view similar to Fig. 1 wherein certainof the screen elementsare shown as formed of dots.

Fig. 6 is a view similar to Fig. 2 wherein certain ofthe screen elementsare shown as formed of dots.

Fig 7 is a transverse section of a double width screen film negativematerial comprising a thick Celluloid support, a substratum layer, and apair of two-color filters, and bearing a pair of black silver primaryimages of negative character. 'l

Fig. 8 is a transverse section ofa double width screen film positivematerial 'bearin a pair of secondary images.

Fig. 9 is a transverse section of a double width screen film positivematerial comprising a celluloid support, a substratum layer, and a pairof two-color filters, and bearing a pair of black silver imagesof-negative character which serve to block out all the parts of thescreens not required as parts of the images.

Fig. 10 is a plan view of a piece of double width film bearing aconventional design.

In all the above drawings the lines and dots are shown very coarse andwide apart for clearness of illustration, but in practice areexceedingly fine, about 500 to the inch and grains finer still.

The ninvention applied to cinematography,

' As the operations are the same for small non-cinematograph picturesand for cinematograph pictures upon continuous lengths of film and asthe invention will doubtless be used to a much greater extent for thelatter form of pictures, the following description the lines beingpreferably Structure of the negative material The following is a briefand general description of the negative film-material, a

more detailed description of the material and method of its manufacturebeing given in the pending application Serial No. 711,254, filed May 5,1924.

The special film-material upon which the vnegatives are photographed isof the class known as screen film. By this is meant that the transparentCelluloid base is provided with two color-filters (Figures 1 to 6) inthe form of very fine multi-colored screens printed or formed upon asubstratum amalgamat- `ed upon the face of the Celluloid(oralternatively they may be printed direct upon the celluloid itself),and these screens are afterwards covei'ed with a high-speed panchromaticgelatino-silver-bromide emulsion.

The base used for the negative film (Fig. 7) is preferably of the fullstandard thickness (about .0045 inch) ,4 and when the substratum,screen, and sensitized layers are added the total thickness of thelnegative film is about .0065 inch. A.

Exposure of this negative film in the camera is made with theltransparent base of Celluloid or other material facing towards the lensand thc sensitized side turned away from the lens, so that light passesfirst through the transparent base (Figure 7), then through themulti-color light-filter, and finally reaches the panchiomatic emulsion,upon which it forms a pair of section-images, each image representingtwo different color-sensations according to the color of the light whichthe filter has allowed to pass, and the two images representing four orthree such colorsensations."

For four-color negatives The filter-screen for four-color consists of animmense number of exceedingly fine colored dots, lines or mosaic pattern3 and`5) These are arranged in two groups, side-by-side upon the twohalves of the double-widths film strip. One section consists of dots(Figure 5), lines (Figure l) or mosaic pattern (Figure 3) of two colorsr (Figs. 1,

lili) llO Each half of the double-width film therefore contains its owncomplementary color, and the two halves are also complementary to cachother.

For three-color negatives rlhe` filter-screen for three-color is of .asimilar character consisting of fine dots, lines, or mosaic pattern, butthe colors comprise only crimson-red, blue-green, and blue-violet(Figure 2) and are therefore only semi-complement-ary. rifhey arearranged in two groups, one upon each half of the doublewidth film as inthe preceding example, but one of the colors is repeated upon each half.For example one half-width may have a filter-screen ofl red and green,and the other a filter-screen of blue-violet and green. 0r any otherpreferred arrangements of the combination may be used; for instance byduplicating'the yellow filters on the negative the complementary color,blue-green, will predominate in the positive because it will beduplicated upon 'both halves (Figures 4 and 6) Producing the original(camera) 'negatives The sources of many of the difficulties which occurin the later stages of making the print itself in some other systems ofcolor cinematography are found at the very commencement of operations,viz at the camera and optical section,and in the present invenvresultsit is necessary to have four sectionnegatives, each representative of adifferent color sensation; and for three-color results threesection-negatives are necessary.

To secure perfect results all section-negatives must be made bysimultaneous exposures at the same moment, in order to secure in eachthe same identical phase of the subject-movement for eachsection-picture.

They must therefore all be exposed by means of only one lens in order tosecure the same view point.

Photographing 1 each section-picture one after the other in alternatingarrangement, as proposed in some systems, shows imagemovement betweenthe section-negatives of every picture, and this is again reproducedinthe positive picture, resulting when the picture -is projected on thescreen in the serious' image-displacement technically known as fringing.Photographing the sections simultaneously by means of two or more ad]accnt lenses, as proposed in some systems, pro- A duces the alternativeobjection of image-displacement due to parallax.

It. has therefore been sought by man investigators' to cure all thesefaults by p otographing through one lens, and then splitting the lightof the primary image so that it forms two or more section-images bymeans of prisms, mirrors, partial reflectors, grids, or the like. Thesemethods are all more or less feasible or satisfactory for producingtwocolor pictures, as the primary image has to be only once split toform two section-images;

but when the primary has to be divided into three in order to producethree section-images the optical difficulties are greatly increased, andthe cost, bulk, and complexity of the optical devices are very muchincreased; but when films ofl single-width; or alternatively if thesection-pictures were taken on ordinary films of single width two filmswith a double-tier of two pictures upon each would be required, or asingle film with a quad-tier of four pictures. If only a three-colorpicture is desired objections of a similar nature arise.

To produce either four or three color-section negatives splitting thelight is preferable to the image-displacement which results from twosuccessive exposure movements.

By the present invention all these several objections are overcome andit becomes almost as simple to produce cinematograph pictures of fourcolors as it was formerly to produce pictures of only two colors. Thefour-color analysis in the negative is secured py using a particularcombination, as folows Uombz'mztz'on for producing four-color negatives.At one camera-empoawre The necessary elements of this combinationcomprise the following:-

(l) A double-width strip of negative film; with a two-colorfilter-screen of dot, line or mosaic pattern (Figures 1, 3 and 5) incolors such as crimson-red and blue-green, formed upon one half of thedouble film, and another similar two-color lter-screen such asblueviolet and orange-yellow, formed upon the other half of the doublefilm; the Celluloid side of the film being turned towards the lens, andthe light passing through the two screens on to the panchromaticsensitive layer placed furthest from the lens (Figure 7) (2) Oneexposure-lens; and

(3) One light-splitting prism, mirror, or equivalent optical device,dividing the original image into two and passing the resulting two imae-beams through the two filtersoreens o the two film-sections, andforming at the focal plane two images of identical size.

By this means four negative section-images in the form of twohalf-pictures are formed by one lens, from one view point, at oneinstant, by one exposure, upon one double-picture-area of onenegative-film strip.

Producing the printing-clichs Having made the camera exposure andobtained the original negative-records by the method described, it isnow necessary to produce a printing-clich from which the finalpositive-records for exhibition can be printed. At this stage thereforeeither of the following alternative courses are open (A) The original(camera) negative (which is complementary in its coloring to the actualscene photographed) may be used to produce a corrected positive byprinting from the original negative through a lens on to a positive filmof similar character, also provided with similar color filters andpanchromatic emulsion, in which case the colors on the resultingpositive will be again reversed and therefore will be the same as vthosein the original scene or object (Figure 8) (B) The original (camera)negative may be treated by theusual reversal baths and treatment bywhich it can be converted from a negative of incorrect or complementary1 colors into a positive of correct or non-complementary colors, `sothat the real coloring of the scene or object is produced on theloriginal film.

(C) A positive in black and White can be reproduced from the colorednegative A, or a negative in black and white can be reproduced from thecoloredy positive B, by copying through a lens and camera.

" Preferred form of printing-clichs Of these several methods it ispreferred in commercial manufacture not to use the original (camera)negative, because of the labor involved in treating continuous lengthsof film to the processes of reversal, and also because of the danger ofdamaging the origi inal negative in the processes.

It is therefore preferred to make a reproduction from the original(Figure 8), and further because by making such reproduction thenecessary reversal of image is simulta-l neously effected. Therefore apositive print is made from the original negative by copying in a camerathrough a lens and developing the .image in the usual way, in accordancewith method` A. This will produce acopy in which the black-silver imageswill be of positive character, and this copy-is used as theprinting-clich from which the actual exhibition positives (Figure 9) arereproduced.

Therefore in ltheir final reproductions for exhibition purposes(produced according to `the co-pending application Serial No. 711,254hereinbefore referred to) the black-silver images will be of negativecharacter and the color-screens visible through them willbe of positivecharacter.

Producing the color positives Having described the methods of producingthe original negatives which constitute the primary images, and theprinting-clichs which constitute the secondary images, it now onlyremains to describe the production of the final positives forexhibition, or third images.

Film-material for color-positives But for cinematograph positives thefilmg material is made of double standard width (Fig. 9).

Otherwise the positive film-material is similar to that used for theoriginal negatives and intermediate printing-clichs; but the speed ofthe sensitive emulsion may be slower and its grain therefore finer.

Printing the color positives In the present process each pair of differ-Ordinary non-cinematograph positives ofential positive images is printedin one layer of non-colored sensitive silver-emulsion, behind a screenof colored lines, dots, or other pattern which are visible bytransmitted light only to the extent allowed by the silver image,

which formsla mask or cut-out fo I. portions of the coloring and allowsthe remainder to pass lthrough and constitute the positive picture(Figure l1).

The positive process used in this invention 4is therefore quitedifferent from the processes heretofore used. In the present inventionall the images are lof black-silver in the form of black and whitetransparencies, superimposed,

upon colored screens which cover the whole of the base of the film orplate. y

Vhat I claim asmy invention and desire of the base of the film or p1ate.

l. A method of producing a photograph in the form ofva.; multi-colortransparency which consists in photographically splitting the originalscene or picture 'into two com ponent half-pictures in twomosaic-colormesma 'picture-area, each half-picture image represcnting adifferent pair of colors from the other, and photograpliicallyreproducing from the half-pictures of negative character a further twohalf-pictures, but ofpositive character, upon another transparentsupport also of double-picture-area having a sensitized pancliromaticemulsion layer attached to the support and two mosaic-color-screensformed side-by-side upon the support between it and the emulsionthereon, one screenrepresenting and filtering one pair' of colors andthe other screen a different pair of colors.

2. A method of producing a photograph in the form of a multi-colortransparency which consists in photographically splitting the originalscene or-picture into two conipoiient half-pictures in twomosaic-colorscreen images of negative character upon a transparentvsensitized support of doublepicture-area, each halfpicture imagerepresenting a different pair of colors from the other, byphotograpliically producing two images of identical size and negativecharacter upon the one sensitized support of double-area and by passingthe light rays of such images through a pair of mosaic-colormy hand ilarsensitive mosaic-color-screenifilm-material, and finally producing .byprojection from the intermediate printing-clichs a pair of iinalv imagesof positive character upon similar sensitive mosaic-color-screenfilm-niateri al of double-area and having two screens sidc-by-side, adiiferent pair of colors being represented in each positive image.

4. The method of multi-color photography as described in claim 2whereinthe pair of color screen negatives, the pair of` intermediateprinting-clichs, and the pair of color screen positives are each formedside-by-side upon supports of double width and doublearea.

The method of producing a multi-color transparency which consists inphotographing through a single lens and prism, split ting the pictureinto two arts on to a sensitive paiiclironiatic screen lm to form twohalfpicture negatives, and printing from suc h negatives on to asensitive panchromatic screen film toproduce two half-picture positivesof two colors each. In testimony whereof J'oHN EDWARD THoaN'roN.

screens formed between the double-area suprt and a sensitivepanchromatic emulsion layer attached to the support, one screenrepresenting and filtering the other screen a diierent pair of colors,

'thus producing four analyses of color within twopicture areas upon theone support of double area, photographically reproducing from these twohalf-pictures two intermediate half-pictures in the 'form ofprintingclichs, also of negative character, upon the `double-areatransparent sensitive screen-{ilmmaterial, photographically reproducingfrom the two printing-clichs of negative character a further twohalf-pictures, but of positive character, also upon a tra arent sup-`port of double-picture-area,- Vand y printi from the printing-clichs onto the sensit positive support, such double-area support having asensitized panchromatic emulsion layer attached to the sup rt and twomosaiccolor-screens formed Vsi e-by-side upon the one pair of colors andl support between emulsion and support, one i producing apair-oflprimaryiinag'es ofintermediate screen representing and.filtering one pair of 1 colors and the other screen a different pair ofcolors.

'3. A method oproducing a multi-colored transparent photograph whichcomprises tive character upon a sensitive mosaici-colorscreenfilm-material of double-width with two screensside-by-sideeachecontaining two colors, one pair of colors beingdifferent from the other pair, producing therefrom a l. air

printing-clich secon images also of negative character, uponsin-- ofnega-

